A common control section (common section) lets you describe a common storage area in one or more source modules.

When the separately assembled object modules are linked as one program, the required storage space is reserved for the common control section. Thus, two or more modules can share the common area.

Only the storage area is provided; the assembler does not assemble the source statements that make up a common control section into object code. You must provide the data for the common area at execution time.

The assembler assigns locations to the symbols you define in a common section relative to the beginning of that common section. This lets you refer symbolically to the data that is placed in the common section at execution time. If you want to refer to data in a common control section, you must establish the addressability of the common control section in each source module that contains references to it. If you code identical common sections in two or more source modules, you can communicate data symbolically between these modules through this common section.